Slip feed roller feeding

ABSTRACT

A method and assembly provide a feed roller that is designed to slip when a foreign object, not designed to be fed by the feed roller, engages the feed roller. One or more rollers are mounted on a shaft and have a grooved surface spring pressed into engagement with a pin extending radially outwardly from the shaft. When a force is applied to the circumference of the roller greater than the force applied by a spring which biases the grooved surface into contact with the pin, the roller will slip, and substantially stop rotating. Since the shaft continues to be driven, if the foreign object is removed the next time the grooved surface is aligned with the pin it will be biased into engagement with the pin so that that roller automatically starts to rotate and provide a feeding action again.

BACKGROUND AND SUMMARY OF THE INVENTION

[0001] There are many situations in which it is desirable to be able tofeed mailing media, or like sheet material (such as documents) that arerelatively thick, e.g. having a nominal thickness of at least about0.125 inches (e.g. about 0.33 centimeters). However if such thickermedia or sheet material is being fed, it is possible that a foreignobject can be jammed into association with a feed roller; for example anoperator's finger or piece of clothing, or hair, or a pencil or pen,might be jammed into contact with a feed roller. If the feed rollercontinues to be driven then the feed roller or shaft may break, or othercomponents of the equipment with which the feed roller is associated canbe mangled, or the clothing or safety of the operator may be adverselyaffected.

[0002] According to the present invention a media moving assembly, and amethod of feeding mailing media or other sheet material, are providedwhich overcome the problem identified above. The invention is applicableto a wide variety of equipment, including addressing printers such asdisclosed in U.S. Pat. Nos. 5,163,669 and 5,401,013 (the disclosures ofwhich are hereby incorporated by reference herein), but the invention isnot restricted to addressing printers, but can be utilized in many otherdifferent types of conventional equipment in which a sheet is beingautomatically fed by a feed roller system.

[0003] According to the most basic concept of the present invention, oneor a plurality of rollers is or are mounted on a driven shaft in such away that if a foreign object engages a roller the roller slips on theshaft while the shaft continues to rotate. The slipping action isentirely automatic. Also it is preferred according to the invention thatonce the foreign object is removed that the roller automatically willcontinue to be driven by the shaft.

[0004] According to the invention this basic functionality isaccomplished in a very simple and inexpensive manner utilizing one ormore pins which extend radially through the shaft and are engaged bygrooved surfaces operatively connected to (e.g. fixed to) one or morerollers, with a spring biasing each grooved surface into contact with apin. Where the biasing force of the spring is overcome by an objectengaging the peripheral surface of the roller to retard its rotation,the pin will be disengaged from the grooved surface so that the rollerremains stationary while the shaft continues to rotate.

[0005] According to one aspect of the present invention there isprovided a media moving assembly comprising: A shaft. A roller mountedon the shaft. A pin extending radially outwardly from the shaft. Agrooved surface operatively connected to the roller. And, a spring whichbiases the roller grooved surface into contact with the pin, so that thepin and grooved surface provide a slip connection between the roller andshaft.

[0006] The spring may comprise a coil spring surrounding the shaft, andthe pin may be substantially circular in cross-section and the groovesubstantially V-shaped, although other configurations of pins andgrooves may be provided.

[0007] Normally the roller comprises a first roller having a firstgrooved surface operatively connected thereto (e.g. fixed thereto,although the engagement may just be an abutting engagement with thegrooved surface and roller maintained in contact by the spring bias),and the pin comprises a first pin. In this case there also is at least asecond roller on the shaft and a second pin extending radially outwardlyfrom the shaft, and a second grooved surface operatively associated withthe second roller spring biased into engagement with the second pin. Asingle coil spring may be provided surrounding the shaft and extendingbetween the first and second rollers and simultaneously biasing thefirst and second rollers toward engagement with the first and secondpins, respectively. First and second washers may be provided between thecoil spring and the first and second rollers. The assembly may alsocomprise a plurality of additional rollers mounted on the shaft, and aplurality of additional pins, and at least some of the additionalplurality of rollers having a grooved surface spring biased intoengagement with a pin.

[0008] While a wide variety of different types of rollers may beutilized, the rollers may comprise a hard plastic body roller having aresilient material circumferential covering, as is common in feedrollers associated with mailing media printers. The shaft may be mountedin a mailing media printer, or other type of printer, and the assemblymay further comprise means for rotating the shaft so that the rollers onthe shaft engage media in a stack to feed the media from the stack intothe printer. The means for rotating the shaft may be a motor, a geartrain, or chain and sprocket assembly, belt and pulley assembly, or anyother conventional structure for that purpose. The invention is ideallysuited for address printers such as shown in U.S. Pat. Nos. 5,163,669and 5,401,013 with the rollers associated with a stack of mailing mediaor other sheet material and feeding the media one at a time from thebottom of the stack into the address printer.

[0009] Each pin preferably has a portion thereof on each side of theshaft, and each grooved surface has a groove on each side of the shaft,so that two portions of each pin engage two grooves of the groovedsurface. Alternatively more than two pin portions may extend radiallyoutward from the shaft and the grooved surface may have more than twogrooves; or one pin portion and one groove may be provided. Where twopin portions and two grooves are provided preferably a single pinextends radially through the shaft to define portions on either side ofthe shaft, although alternatively the pin portions may be welded to,molded with, or otherwise affixed to the shaft and simply extendoutwardly from the peripheral surface thereof.

[0010] According to another aspect of the present invention there isprovided a method of feeding mailing media having a normal thickness ofat least about 0.125 inches, comprising: (a) Engaging the mailing mediahaving a normal thickness of at least about 0.125 inches with aplurality of drive rollers rotating with a common shaft to move themedia in a first direction. And, (b) if one or more of the rollersengage a foreign object, causing the one or more rollers engaging theforeign object to automatically substantially stop rotating whilerollers not operatively engaging the foreign object continue to rotate.

[0011] The method as set forth above may further comprise (c) whenengagement of the foreign object with the one or more rollers isterminated, automatically causing those one or more rollers to continuerotating and engaging and moving the mailing media. For example (a)through (c) may be practiced using a shaft having a plurality of pinsextending radially outwardly from the shaft, and a grooved surfaceoperatively connected to each roller having the grooved surface thereofengaging one of the pins, and a spring which biases each roller groovedsurface into contact with a pin. In many circumstances (a) is practicedto move the mailing media from a stack in a first direction away fromthe stack. For example (a) may be further practiced to engage and movethe bottom of the lowest mailing media in the stack.

[0012] According to another aspect of the present invention there isprovided a method of feeding sheet material, comprising: (a) Engagingthe sheet material with a plurality of drive rollers on a common shaftto move the sheet material in a first direction. (b) If one or more ofthe rollers engage a foreign object, causing the one or more rollersengaging the foreign object to automatically substantially stop rotatingwhile rollers not operatively engaging the foreign object continue torotate. And, (c) when engagement of the foreign object with the one ormore rollers is terminated, automatically causing those one or morerollers to continue to rotate, engaging and moving the sheet material.The details of the practice of procedures (a) through (c) may be as setforth above.

[0013] It is the primary object of the present invention to provide asimple and effective slip feed roller assembly and method of utilizationthereof to minimize damage to feed roller assemblies, and enhance thesafety and integrity of persons or implements around the feed rollerassembly. This and other objects of the invention will become clear froman inspection of the detailed description of the invention and from theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a side schematic view of an exemplary feed rollerassembly according to the present invention, with the roller and springshown in longitudinal cross-section and the shaft shown in elevation;

[0015]FIG. 2 is a side view of the assembly of FIG. 1 showing the rollerengaging the lowest piece of mailing media in a stack and feeding it ina given direction;

[0016]FIG. 3 is a side detail view of an exemplary roller according tothe invention showing a slipped condition between the shaft pin androller grooved surface, in which position the rotating shaft will notdrive the roller;

[0017]FIG. 4 is a side detail view of the roller when in the position ofFIG. 3, with the roller and spring shown in cross-section and the shaft,pin, and grooved surface in elevation; and

[0018]FIG. 5 is a schematic detail view showing an exemplary pin restingin an exemplary groove in a roller system according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0019] An exemplary roller assembly according to the present inventionis shown generally by reference numeral 10 in FIG. 1. It includes ashaft 11 and a plurality of rollers 12 mounted on the shaft. The shaft11 is rotated by a suitable rotating means, shown schematically in FIG.1 as a motor 13. However the shaft 11 can be rotated by any conventionalrotating means such as gears, belts and pulleys, sprockets and chains,etc.

[0020] The shaft 11 and the rollers 12 as illustrated in FIG. 1 are ofthe type that is typically used in a feed roll assembly for anaddressing printer, such as shown in U.S. Pat. No. 5,401,013. However itis to be understood that other types of shafts and rollers may beprovided. In the embodiment illustrated in FIGS. 1 and 2, the shaft 11is preferably of metal or hard plastic, while each of the rollers 12comprises a central tubular portion 13 having an internal diameterslightly greater than the external diameter of the shaft 11 and notkeyed to the shaft, a radially extending disc or arms 14, a peripheraltubular element 15, and a circumferential covering 16. The components 13through 15 are preferably integrally molded from hard plastic while thecircumferential covering 16 is of a resilient material, such assynthetic or natural rubber.

[0021] In one specific exemplary, but non-limiting, embodiment of theinvention, for use in a printer such as in U.S. Pat. No. 5,401,013, therollers 12 have an outside diameter of about 2.4-2.8 inches (e.g. 2.6inches), the hub or body (formed by elements 13-15) is of nylon withabout 20-40% (e.g. about 30%) glass bead fill, the covering 16 isNitrile rubber having a durometer of about 10-30 (e.g. about 20) ShoreA, and the shaft 11 is 4150 high carbon steel.

[0022]FIG. 2 schematically illustrates one exemplary use of the feedroller assembly of FIG. 1, in association with an address printer suchas shown in U.S. Pat. Nos. 5,163,669 or 5,401,013. Shown in dotted lineat 20 is an element that is adapted to define a gap 21 between it andthe circumferences 16 of the rollers 12 so as to accept mailing media22, or like sheet material (such as documents), having a given thickness23 therebetween. The element 20 may be any conventional element such asanother roller, a segmented or continuous flat or curved surface, or awide variety of other conventional components.

[0023] In the typical use of the feed roller assembly 10 the motor 13drives the shaft 11 so that the roller 12 rotates in the direction 24seen in FIG. 2, and each mailing media 22 (such as a stuffed envelope)has the under surface 25 thereof engaged by the circumference 16 of someor all of the rollers 12 to drive the media 22 in the direction 26through the gap 21. The next sheet 22 then automatically comes intocontact with the rotating rollers 12, to be driven next through the gap21 in the direction 26. The direction 26 typically leads to a printer orother sheet handling equipment.

[0024] Especially if media 22 having a thickness 23 of about 0.125inches (about 0.33 centimeters) or more is to be handled, which requiresan appropriate adjustment between the element 20 and the rollers 12 (asin U.S. Pat. No. 5,401,013), there is a danger that a foreign object,such as hair, a finger, a piece of clothing, a pen or pencil, a paperclip, or the like, could engage one or more of the rollers 12, andperhaps become wedged in the gap 21. This could have a number of adverseaffects including breaking or otherwise harming one or more of therollers 12, breaking a drive component for driving the shaft 11, causingother damage to the equipment, causing damage to the foreign object,and/or presenting a safety hazard to the operator, especially if theoperator's clothing, hair, or finger is the foreign object.

[0025] In order to avoid the problems set forth above, in a very simpleyet effective manner according to the invention a slip arrangement isprovided between at least some of the rollers 12 (preferably all of therollers 12) and the shaft 11 so that if a roller 12 should be engaged bya foreign object so that its rotation in the direction 24 is arrested,the roller 12 will stop while the shaft 11 continues to rotate, withsubstantially no damage or harm either to the equipment or the foreignobject.

[0026] The simple slip connection according to the present inventionpreferably comprises, associated with each roller, a pin 30 which isconnected to and rotatable with the shaft 11, and a grooved surfaceelement 31 which is operatively connected to the roller 12. Preferablythe grooved surface element 31 is affixed to the roller 12, although itmay simply be spring pressed into contact therewith, and the element 31keyed to the roller 12 in some manner (such as to the inner tubularportion 13 thereof). A spring, such as a coil spring 32 illustrated inFIGS. 1 and 4, biases the grooved surface element 31 into contact withthe pin 30 so that normally the roller 12 rotates with the shaft 11.However should the force engaging the roller 12 and arresting itsrotation be larger than the force applied by the spring 32, then the pin30 will pop out of the grooved surface of the element 31 and the shaft11 will continue to rotate while the roller 12 does not. For thespecific exemplary, but non-limiting, embodiment of the rollers 12 andshaft 11 described above, the spring 32 could have a rate between about30-32 lbs./in. (e.g. about 31.1 lbs./in.) and an installed force betweenrollers 12 of about 10-12 pounds (e.g. about 11 pounds).

[0027] One preferred embodiment of the pin 30 and the grooved surfaceelement 31 is best illustrated in FIGS. 3 through 5. FIGS. 3 and 4 showthe components 30, 31 in a non-driving condition where the force on theroller 12 was greater than the spring force of the spring 30 so that thepin 30 popped out of the groove or grooves 33 in the surface 34 of thegrooved surface element 31. As seen in FIGS. 3 and 4 the pin 30 hasfirst and second portions 35, 36, thereof that extend radially outwardlyfrom the shaft 11. While the portions 35, 36 may be integrally moldedwith the shaft 11, or welded or otherwise affixed to the exteriorsurface thereof, in the preferred embodiment the pin 30 simply is longenough to extend completely through the shaft 11 and have aninterference fit therewith, with the portions 35, 36 extending radiallyoutwardly from the shaft 11 approximately equal distances on oppositesides of the shaft 11. For example, the pin 30 could be a hardened steeldowel pin.

[0028] In the embodiment of FIGS. 3 and 4 preferably two grooves 33 areprovided in the grooved surface 34, one on each side of the shaft 11,and for one groove 33 for cooperation with each pin portion 35, 36.However more grooves 33 than pin portions 35, 36 may be provided. Whiletwo pin portions 35, 36 and two grooves 33 are preferred, more of eachmay be provided.

[0029] In the embodiment illustrated in FIGS. 3 through 5 the pinportions 35, 36 are preferably circular in cross section (as mostclearly seen in FIG. 5) while the grooves 33 are substantially V-shapedin cross-section, and the components dimensioned so that pin portions 35will sit in the grooves 33 as illustrated in FIG. 5 when pressed by thesprings 32. However other shapes may be provided for both the pin 30 andthe grooves 33. For example the pin portions 35, 36 could have polygonalshapes in cross-section, while the grooves 33 could be rounded, havemultiple surfaces (for example corresponding to multiple surfaces onpolygonal shaped pin portions 35, 36), or the like.

[0030] In the preferred embodiment illustrated in the drawings(particularly see FIGS. 1 and 4) the spring 32 for biasing comprises acoil spring 32 that surrounds the shaft 11 and acts between two rollers12, biasing them away from each other and with the grooved surfaceelement 31 thereof into contact with pins 30. Preferably each spring 32engages a washer 38 (see FIG. 4) at each end thereof to ensure optimumoperability.

[0031] In the method according to the present invention utilizing theassembly 10, mailing media 22, or like sheet material, having a nominalthickness of at least about 0.125 inches is engaged with a plurality ofdrive rollers 12 on a common shaft 11, to move the media in the firstdirection 26. If one or more of the rollers 12 engage a foreign object,causing the one or more rollers 12 engaging the foreign object toautomatically substantially stop rotating while rollers 12 notoperatively engaging (that is not effectively stopped by) the foreignobject continue to rotate in direction 24. The method also preferablycomprises, when engagement of the foreign object with one or morerollers is terminated, automatically causing those one or more rollers12 to continue rotating, and engaging and moving the mailing media 22.This is effected since with the pin 30 and grooved surface element 31 inthe position illustrated in FIGS. 3 and 4, when the object is removedfrom engagement with the roller 12 when the shaft 11 rotates to theposition where the pin portions 35, 36 are aligned with the grooves 33,the biasing force of the spring 32 will now cause the grooves 33 to bepressed into engagement with the pin portions 35, 36, which then againresults in rotation of the roller 12 in the direction 24 and thus movingof the media 22 in the direction 26. The shaft 11 continues to rotate,during the practice of the method, and substantially no damage to anycomponent of the assembly 10 or associated printer or other device, norto the foreign object, results.

[0032] It will thus be seen that according to the present invention asimple yet effective method and apparatus are provided for minimizingdamage to machine components, or foreign objects, during automaticfeeding of mailing media or other sheet material to a utilization devicesuch as a printer. While the invention has been herein shown anddescribed in what is presently conceived to be the most practical andpreferred embodiment thereof it will be apparent to those of ordinaryskill in the art that many modifications may be made thereof within thescope of the invention, which scope is to be accorded the broadestinterpretation of the appended claims so as to encompass all equivalentassemblies and methods.

What is claimed is:
 1. A method of feeding mailing media having a normalthickness of at least about 0.125 inches, comprising: (a) engaging themailing media having a normal thickness of at least about 0.125 incheswith a plurality of drive rollers on a common shaft to move the media ina first direction; and (b) if one or more of the rollers engage aforeign object, causing the one or more rollers engaging the foreignobject to automatically substantially stop rotating while rollers notengaging the foreign object continue to rotate.
 2. A method as recitedin claim 1 further comprising (c) when engagement of the foreign objectwith the one or more rollers is terminated, automatically causing thoseone or more rollers to continue rotating, engaging and moving themailing media.
 3. A method as recited in claim 2 wherein (a)-(c) arepracticed using a shaft having a plurality of pins extending radiallyoutwardly from the shaft, and a grooved surface operatively connected toeach roller having the grooved surface thereof engaging one of the pins,and a spring which biases each roller grooved surface into contact witha pin.
 4. A method as recited in claim 1 wherein (a) is practiced tomove the mailing media from a stack in a first direction away from thestack.
 5. A method as recited in claim 4 wherein (a) is furtherpracticed to engage and move the bottom of the lowest mailing media inthe stack.
 6. A method as recited in claim 2 wherein (a) is practiced tomove the mailing media from a stack in a first direction away from thestack.
 7. A method as recited in claim 6 wherein (a) is furtherpracticed to engage and move the bottom of the lowest mailing media inthe stack.
 8. A method of feeding sheet material, comprising: (a)engaging the sheet material with a plurality of drive rollers on acommon shaft to move the sheet material in a first direction; (b) if oneor more of the rollers engage a foreign object, causing the one or morerollers engaging the foreign object to automatically substantially stoprotating while rollers not engaging the foreign object continue torotate; and (c) when engagement of the foreign object with the one ormore rollers is terminated, automatically causing those one or morerollers to continue rotating, engaging and moving the sheet material. 9.A method as recited in claim 8 wherein (a)-(c) are practiced using ashaft having a plurality of pins extending radially outwardly from theshaft, and a grooved surface operatively connected to each roller havingthe grooved surface thereof engaging one of the pins, and a spring whichbiases each roller grooved surface into contact with a pin.
 10. A methodas recited in claim 8 wherein (a) is practiced to move the sheetmaterial from a stack in a first direction away from the stack.
 11. Amethod as recited in claim 10 wherein (a) is further practiced to engageand move the bottom of the lowest sheet of sheet material in the stack.12. A media moving assembly comprising: a shaft; a roller mounted onsaid shaft; a pin extending radially outwardly from said shaft; agrooved surface operatively connected to said roller; and a spring whichbiases said roller grooved surface into contact with said pin, so thatsaid pin and grooved surface provide a slip connection between saidroller and shaft.
 13. An assembly as recited in claim 12 wherein saidspring comprises a coil spring surrounding said shaft.
 14. An assemblyas recited in claim 12 wherein said pin is substantially circular incross-section and said groove is substantially V-shaped.
 15. An assemblyas recited in claim 12 wherein said roller comprises a first rollerhaving a first grooved surface operatively connected thereto, and saidpin comprises a first pin; and further comprising at least a secondroller on said shaft, and a second pin extending radially outwardly fromsaid shaft, a second grooved surface operatively associated with saidsecond roller spring biased into engagement with said second pin.
 16. Anassembly as recited in claim 15 wherein a single coil spring surroundingsaid shaft extends between said first and second rollers andsimultaneously biases said first and second rollers toward engagementwith said first and second pins.
 17. An assembly as recited in claim 16further comprising first and second washers between said coil spring andsaid first and second rollers.
 18. An assembly as recited in claim 16wherein said spring has a rate of between about 30-32 pounds/inch and aninstalled force of between about 10-12 pounds, and said rollers have anoutside diameter of between about 2.4-2.8 inches.
 19. An assembly asrecited in claim 18 wherein each of said pins is substantially circularin cross-section and each of said grooves is substantially V-shaped, andeach of said pins has a portion thereof on each side of said shaft andeach of said grooved surfaces has a groove on each side of said shaft,so that two portions of each pin engage two grooves of said groovedsurface.
 20. An assembly as recited in claim 12 wherein said groovedsurface is fixed to said roller.
 21. An assembly as recited in claim 15further comprising a plurality of additional rollers mounted on saidshaft, and a plurality of additional pins, and at least some of saidadditional plurality of rollers having a grooved surface spring biasedinto engagement with a pin.
 22. An assembly as recited in claim 21wherein said shaft is mounted in a printer; and further comprising meansfor rotating said shaft so that said rollers on said shaft engage mediain a stack to feed the media from the stack into said printer.
 23. Anassembly as recited in claim 12 wherein said roller comprises a hardplastic body roller having a resilient material circumferentialcovering.
 24. An assembly as recited in claim 14 wherein said groovedsurface is fixed to said roller; and wherein said pin extends throughsaid shaft and has a portion thereof on each side of said shaft and saidgrooved surface has a groove on each side of said shaft, so that twoportions of each pin engage two grooves of said grooved surface.
 25. Anassembly as recited in claim 23 wherein said roller body comprises nylonwith between about 20-40% glass bead fill, and said resilient materialis Nitrile rubber having a durometer of between about 10-30 Shore A.